The move is expected to affect the sales of 10.5 million light bulbs this year, saving $35.6 million in energy bills. The gain in efficiency is estimated at around 30 percent.

The new bulbs look just like the old ones, and fit the same sockets. They're also just as bright, and cost the same amount. They're quite a bit cheaper than the curly CFLs that have become common in homes and offices. Lower-watt versions of smaller bulbs will also be produced.

One major advantage of the new bulbs is that they don't produce as much heat as the old ones. That helps conserve power by concentrating energy on generating light.

Don't worry -- nobody's going to be checking the wattage of your sockets anytime soon. You can keep your old bulbs for as long as they last. And if merchants have old bulbs on the shelves, they're still allowed to sell them until the stock runs out.

As usual, California is leading the way on energy innovation. The rest of the country will follow the state's lead in exactly one year.